® Design Idea DI-39 ® TOPSwitch-GX 13 W, Universal Input DVD Supply with 70 mW No-load Application Device Power Output Input Voltage DVD TOP244P 13 W (17 W pk) 85-265 VAC Design Highlights • • • • • • • Output Voltage 3.3 V / 5 V / 12 V / -12 V Topology Flyback The supply operates at full frequency at high and medium power and reduces frequency at light loads. Components D9 and C10 rectify and filter the bias voltage. High efficiency multi-ouptut flyback (77% minimum) Topology scalable to higher powers Excellent cross-regulation Excellent input no-load consumption <70 mW input 132 kHz switching frequency allows smaller transformer Frequency jitter eliminates common-mode EMI choke >10 dB margin against CISPR22-B conducted EMI with artificial hand grounding TOPSwitch-GX frequency jitter allows conducted EMI compliance without a common-mode choke, using only capacitors C1, C4 and inductor L1 as an EMI filter. Components D5 and C2 form a capacitor clamp circuit absorbing leakage inductance energy during normal operation. Zener VR1 clamps the voltage to a safe level during abnormal and transient conditions. After clamping, reverse current flows through D5, recovering some of the energy. Resistor R5 limits the reverse current and, with R7, improves EMI by limiting the ringing on the drain. Continuous mode operation allows reduced primary and secondary peak currents, optimizing cross regulation and load regulation by minimizing leakage inductance induced voltage shifts. Operation The TOPSwitch-GX uses current mode feedback to achieve excellent no-load standby. Components C16, R1 and Q2 provide a constant current powering the TOPSwitch-GX CONTROL pin. Resistor R2 feeds the remainder of Q2 current to the M pin, reducing TOPSwitch-GX current limit with increased current. Resistor R11 sets the maximum current limit of the device. Components R6, Q1 and C13 implement slope compensation. Resistors R15 and R16 share the feedback from the 3.3 V and 5 V outputs for good cross-regulation. C8 1 nF Y1 L2 3.3 µH D1-D4 1N4005 F1 3.15 A 250 VAC 85 - 265 VAC C3 0.047 µF x2 VR1 P6KE180 C1 33 µF 400V R7 100 Ω C4 33 µF 400V C15 470 µF 25 V D7 UF4003 C11 D11 1800 µF 1N5822 25 V C2 0.01 µF 1 KV D10 1N5822 R5 47 Ω D8 UF4003 D5 1N4007 L4 3.3 µH C12 1000 µF 10 V C9 220 µF 25 V C6 220 µF 25 V R8 1 kΩ C14 0.1 µF D Q2 2N3906 M C13 47 pF CONTROL C R11 7.5 kΩ L1 1.4 µH 0.5 A S C19 0.1 µF R14 6.8 Ω C5 47 µF 10 V R6 20 kΩ C18 470 µF 10 V RTN U2B PC817 PC817 U2A C16 0.33 µF 5 V, 1.6 A 3.3 V, 700 mA C17 470 µF 10 V R9 200 Ω R12 1 1/2 W R1 270 Ω TOPSwitch-GX U1 TOP244P R2 20 kΩ 12 V, 400 mA C20 150 µF 25 V L3 3.3 µH C7 10 µF 50 V U3 TL431CLP R16 6.34 kΩ R15 20 kΩ R10 3.3 kΩ R13 10 kΩ Q1 2N3906 - 12 V, 100 mA D9 C10 1N4148 47 µF 50 V PI-3321-111902 Figure 1. TOPSwitch-GX DVD Player Schematic. . DI-39 www.powerint.com November 2002 DI-39 Key Design Points TRANSFORMER PARAMETERS • Use of foil for the 3.3 V and 5 V windings also helps to optimize cross-regulation. • Optional capacitor C7 is the “soft-finish” capacitor and prevents overshoot on startup. • Compact layout for components D7, D10, D11, C11, C12, C15 will improve cross-regulation and efficiency. Compact layout for L2, L3, L4, C17, C18, and C20 will achieve best output ripple. • Figure 2 shows conducted EMI at 230 VAC full load, with output “Artificial Hand” grounding. Floating output return gives lower results. • Table 2 shows the cross regulation of the supply over load for both 115 VAC and 230 VAC. PI-3408-112502 80 70 60 QP 50 AV dBµV Bobbin EEL25 Vertical 14 Pins Shield: 32T x 2 x 32 AWG Primary: 64T x 2 x 32 AWG Bias: 10T x 4 x 32 AWG Shield: 2T x 8 x 32 AWG +3.3V: 4T x foil 0.052 x 14 mm +5V: 1T x foil 0.052 x 14 mm +12V: 4T x 4 x 32 AWG -12V: 7T x 4 x 32 AWG Winding Details Shield (NC-5), tape, Primary (1-4), tape, Bias (7-6), tape, Shield (5-NC), tape, +12 V (13-8), +3.3 V (11,12-9,10), +5 V (9-10,13), tape, -12 V (14-11, 12), tape Winding Order (Pin Numbers) Primary Inductance (Pins 1-4 all others open) Primary Resonant Frequency Quasi Peak 40 EEL25 Himag MZ4 EEL25.4, Taiwan AL of 344 nH/T2 Core Material Leakage Inductance 30 1.42 mH ±10% at 132 kHz 300 kHz minimum 30 µH maximum Table 1. Transformer Construction Information. 20 10 0 Average -10 -20 0.15 1.0 10.0 -100.0 MHz Figure 2. EMI at 230 VAC Full Load with "Artificial Hand" Grounding of Output. Output Voltage (V) 3.3 5 12 -12 Load Range (%) 10-100 10-100 10-100 100 Cross Regulation (%) -4 -3 -2 -1 0 1 2 3 4 Table 2. Worst Case Cross Regulation at 115 VAC and 230 VAC. For the latest updates, visit our Web site: www.powerint.com Power Integrations reserves the right to make changes to its products at any time to improve reliability or manufacturability. Power Integrations does not assume any liability arising from the use of any device or circuit described herein, nor does it convey any license under its patent rights or the rights of others. The products and applications illustrated herein (including circuits external to the products and transformer construction) may be covered by one or more U.S. and foreign patents or potentially by pending U.S. and foreign patent applications assigned to Power Integrations. A complete list of Power Integrations’ patents may be found at www.powerint.com. The PI Logo, TOPSwitch, TinySwitch, LinkSwitch and EcoSmart are registered trademarks of Power Integrations, Inc. PI Expert is a trademark of Power Integrations, Inc. ©Copyright 2002, Power Integrations, Inc. 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